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Energy yield prediction of a bifacial PV system with a miniaturized test array
摘要： Because of the sensitivity on multiple additional factors, compared to monofacial standard installations, the simulation and prediction of a bifacial PV arrays yield is by far more complicated and less reliable. Accordingly, the determination of optimized installation conditions is considerably less straightforward for bifacial installations. Due to the pronounced dependencies also the assignability of otherwise applied installation conditions to similar systems is limited. Because of the low accuracy of the traditional approaches to predict the bifacial system output the use of a miniaturized test rig might be an interesting option. Provided that the results can be assigned to measurements at real systems it can be used as a cheap and flexible testing device. Miniaturized devices could be used in long-term trials for yield measurements at specific locations, to identify optimum installation conditions or to validate simulation algorithms. Running several test rigs with different configurations in parallel would enable a direct comparison. The small size of a miniaturized rig also allows a fast change of the set-up, which is an interesting feature to test the respective impact at otherwise almost unchanged conditions in short-term tests. In this paper we report on a test device which is a miniaturized (1:12) replica of an existing PV array with commercial bifacial modules. The measurement data of both systems are compared in order to investigate if there is a clear assignability. A unique feature of the large test field, a permanent and automated variation of the tilt angle, is also transferred to the miniaturized version. Accordingly, the whole tilt angle range is tested and potential tilt angle dependent effects are revealed. Based on the obtained data we give an estimation of the error in the prediction accuracy and discuss options for possible improvements.
关键词： Energy yield prediction,Bifacial,Tilt angle,Test system
更新于2025-09-23 15:22:29
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Methodology to Determine Photovoltaic Inverter Conversion Efficiency for the Equatorial Region
摘要： Photovoltaic inverter conversion efficiency is closely related to the energy yield of a photovoltaic system. Usually, the peak efficiency (ηmax) value from the inverter data sheet is used, but it is inaccurate because the inverter rarely operates at the peak power. The weighted efficiency is a preferable alternative as it inherently considers the power conversion characteristics of the inverter when subjected to varying irradiance. However, since the weighted efficiency is influenced by irradiance, its value may not be appropriate for different climatic conditions. Based on this premise, this work investigates the non-suitability of the European weighted efficiency (ηEURO) for inverters installed in the Equatorial region. It utilizes a one year data from the Equatorial irradiance profile to recalculate the value of ηEURO. Furthermore, a new weighted efficiency formula for the Equatorial climate (ηEQUA) is proposed. Validation results showed that calculated energy yield with ηEQUA closely matched the real energy yield of 3 kW system with only 0.16% difference. It is envisaged that the usage of ηEQUA instead of ηmax or ηEURO will results in a more accurate energy yield and return of investment calculations for PV systems installed in Equatorial regions.
关键词： equatorial climate,weighted efficiency,energy yield,PV inverter,conversion efficiency
更新于2025-09-23 15:19:57
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Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions
摘要： Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird’s model has been used as a general spectral model. However, atmospheric parameters such as aerosol optical depth and precipitable water have a constant value in the model that only applies to clear days. In this study, atmospheric parameters were extracted using the Bird’s spectrum model from the measured global spectrum and the seasonal fluctuation of atmospheric parameters was examined. We propose an overcast spectrum model and calculate the all-weather solar spectrum from clear to overcast sky through linear combination. Three types of PV modules (fixed Si, two-axis tracking Si, and fixed InGaP/GaAs/InGaAs triple-junction solar cells) were installed at the University of Miyazaki. The estimated performance ratio (PR), which takes into account incident angle and spectral variations, was consistent with the measured PR. Finally, the energy yield of various PVs installed across Japan was successfully estimated.
关键词： output forecasting,incident angle,energy yield,photovoltaic,precipitable water,aerosol optical depth
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Dependence of Multijunction Optimal Gaps on Spectral Variability and Other Environmental and Device Parameters
摘要： We present a method to calculate the yearly energy production of multijunctions including spectral variations. We use it to find the optimal band gaps yielding maximum energy production. The band gaps found are different to those previously reported when using the standard efficiency as the optimization target. Our calculations predict that novel hybrid tandems in combination with bifacial silicon can lead to energy yields near 1 MWh m?2 year?1 at most locations of interest. We also discuss the effects of changing parameters such as the external radiative efficiency, series resistance, sub-cell thickness, temperatures, and location.
关键词： bifacial,Yearly energy yield,hybrid tandems,multijunctions
更新于2025-09-19 17:13:59
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Online monitoring of roof-mounted stand-alone solar photovoltaic system on residential building
摘要： Advancement in solar photovoltaic (SPV) system technologies over past decades has resulted in regular decrease in prices of the systems world-over. The number of installations is projected to increase manifolds due to proactive Government policies and support for market development. There is need to study performance of already installed systems and establish benchmarks of expected performance in a given region. The benchmarks will be useful for performance contractors as well as users of the systems. Also, there is growing need to create awareness among stakeholders about scope for enhancing performance of the system through effective operation and maintenance of the systems. In the present work, we analyze performance of recently installed roof-mounted stand-alone solar photovoltaic system on a residential building, that is equipped with internet based online performance monitoring platform. This is the ?rst of its kind of work in the region, reporting results of monitoring of performance of a remotely located system, over a period of one full year in the state of Goa, India. The data has been acquired at regular intervals of ten minutes for one year using the platform for online performance monitoring. The results con?rm that the online performance monitoring platform is a potentially advantageous feature of the system for both system integrators as well as system operators or users. The results provide useful basis for comparison of performance in terms of performance ratio and energy yield of the system. The results are also useful for predicting performance and maximizing capacity utilization of the system.
关键词： Performance ratio,Stand-alone SPV system,Online monitoring,Energy yield
更新于2025-09-16 10:30:52
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Perovskite/c-Si Monolithic Tandem Solar Cells Under Real Solar Spectra: Improving Energy Yield by Oblique Incident Optimization
摘要： Many research groups have noticed the performance of rapidly-developed perovskite/silicon monolithic tandem solar cells (TSCs) under real situation, but they overlook the short-current density mismatch of two sub-cells at different times in a day and the spectrum variation at different latitudes. Here we have systematically analyzed the efficiency losses and proposed optimization scheme by combination of experiment and simulation relying on reliable experimental data in a year. We have verified the simulated absorptance spectra varying with incident angle θ to substitute the external quantum efficiency spectra, which makes the optimization at oblique incidence possible. More importantly, we have further calculated and expanded the optimized current losses and energy output enhancement in perovskite/silicon monolithic TSCs to all latitudes. This work can be served as a practical guidance for the design of perovskite/silicon monolithic TSCs with the best annual energy output at different latitudes in the world.
关键词： Perovskite/silicon monolithic tandem solar cells,real solar spectra,efficiency losses,oblique incident optimization,energy yield
更新于2025-09-12 10:27:22
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Performance analysis of mono and poly-crystalline silicon photovoltaic modules under Agadir climatic conditions in Morocco
摘要： The evaluation of a solar photovoltaic (PV) technology helps to identify its suitability for a specific location. The main objective of the present study is to assess the suitability of mono-crystalline silicon (mc-Si) and poly-crystalline silicon (pc-Si) PV modules with almost similar characteristics under Agadir climatic conditions. Electricity yield of these modules is calculated from the uninterruptible measured current–voltage curves from sunrise to sunset during a year. The influence of weather conditions, global irradiance and temperature, on the performances of the modules is assessed and as a part of considerations in the PV power plant design that the output power from pc-Si PV modules is found greater. Calculated annual average final yield (Yf), and performance ratio (PR) for mc-Si and pc-Si PV systems are (1602.22 kWh/kWp, 0.71), (1691.85 kWh/kWp, 0.75) respectively.
关键词： Performance,Outdoor monitoring,Photovoltaic,Energy yield,I–V curves
更新于2025-09-11 14:15:04
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Optimized Design of Silicon Heterojunction Solar Cells for Field Operating Conditions
摘要： Solar modules are currently characterized at standard test conditions (STC), defined at 1000 W/m2 and 25 °C. However, solar modules in actual outdoor operating conditions typically operate at lower illumination and higher temperature than STC, which significantly affects their performance ratio (average harvesting efficiency over efficiency in STC). Silicon heterojunction (SHJ) technology displays both good temperature coefficient and good low-illumination performances, leading to outstanding performance ratios. We investigate here SHJ solar cells that use a-SiCx(n) layer as front doped layer with different carbon contents under different climates conditions. Adding carbon increases transparency but also resistive losses at room temperature (compared with carbon-free layers), leading to a significant decrease in efficiency at STC. We demonstrate that despite this difference at STC, the difference in energy harvesting efficiency is much smaller in all investigated climates. Furthermore, we show that a relative gain of 0.4%–0.8% in harvesting efficiency is possible by adding a certain content of carbon in the front (n) layer, compared with carbon-free cells optimized for STC.
关键词： Energy yield,harvesting efficiency,silicon heterojunction,temperature coefficient
更新于2025-09-11 14:15:04
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Energy yield of all thin-film perovskite/CIGS tandem solar modules
摘要： Perovskite/CuIn1 ? xGaxSe2 (CIGS) tandem photovoltaics (PV) promises high power conversion efficiencies in combination with the advantages of a light weight and an all thin-film PV technology. However, the complexity of perovskite/CIGS tandem solar module architectures requires careful optimization of the layer stack under realistic solar irradiation conditions. Here, we provide a systematic numerical study on the energy yield (EY) of perovskite/CIGS tandem solar modules, optimizing the device architecture with regard to irradiance in various climate zones. In particular, variations of the spectral irradiation and the average photon energy are of decisive importance for the location-specific optimization of the device architecture. Compared with the reference single-junction CIGS thin-film PV technology, we demonstrate a strong improvement in EY (>30%) in perovskite/CIGS thin-film PV for perovskites of a wide range of bandgaps (1.55 - 2.0 eV), reaching up to 52% improvement in EY for the optimal bandgap (around 1.8 eV). Of the two most favored architectures, the two-terminal and four-terminal devices, perovskite/CIGS tandem solar modules with low bandgap (～1.55 eV) perovskite absorbers in the four-terminal architecture outperform those in the two-terminal architecture in average by 3.5% relative. However, for wide perovskite bandgaps ranging from 1.75 eV to 1.85 eV, both architectures perform comparably. The improvements in EY for perovskite/CIGS tandem solar modules highlight the potential of this technology but also the vital need for light management in tandem photovoltaics.
关键词： perovskite/CIGS tandem photovoltaics,energy yield modelling,realistic conditions
更新于2025-09-09 09:28:46